Machine for forming cylindrical cams



A. L. DE LEEUW MACHINE FOR FORMING CYLINDRICAL CAMS Filed April 2, 1926 4 Sheets-Sheet 1 ]vwzuoz A. L. DE LEEUW MACHINE FOR FORMING CYLINDRICL CAMS May 29, 1928.

4 Sheets-Sheet 2 Filed April 2, 1926 May 29, 1928.

A. L. DE LEEUW MACHINE FOR FORMING CYLINDRICAL (FAMS Filed April 2, 1926 4 Sheets-Sheet 3 May 29 1928. 1 671,35&

A. L. DE LEEUW MACHI-BXFOR FORMING CYLINDRICAL CAMS Filed April 2, 1926 4 Sheets-Sheet 4 Patented May 29, 1928.

UNITED STATES ,67, PATENT orrrca:

A DOLPH L: DE LEEUW, OF PLAI1F1ELD, NEW JERSEY, ASSIGNOR T STOKES &; SMI'1 COMPA1\TY OF PHILADELPIIIA, PENNSYLVANIA, A CORPORA'IIOZN QF PENNSYL- VANIA.

MACHINE F013. IEORMING CYLINDRIAL CAMS.

Application filed April 2, 1926. Serial No. 99,226.

This invention embraces a method and an apparatus *for so forming cylindrical cams that they will uniformlyinterfit with a.follower movable in an arcuate path.

Cylindrical cams have habitually been out with the similar elemental point s of their grooves at an invariable di'stance from the axis of rotation of the cam. Or, considering it from another viewpoint, with their linear generants all radial. Where the follower is confined to a straight path parallel with that axis, a uniform fit is thereby procured. But where the follower, as so often is the case, oscillates aboutan external pivot, it has alwa s been necessary, after cutting the roove 111 the preirailing marmer, to expen mach manual eort in altering local regions of the roove to eliminate tenden cies of the fol ower t0 bind. and Cramp. These regions become apparent only after the follower and cam have been assembled and subjected to trial runs. And the corrections have to be made only by removing metal, which thus reduces the area of contact prescribed by the designer with the,ob-

ject of keeping low the subsequent wear.

It is now proposed.by this invention, so to cut the groeve that all such incompatibilities will be initially avoided, and the follower will unif0rmly contact with the walls of the groove in all of its arcuate positions; thereby ensuring smooth action, accurate interfitting, and a-minimum of wear in usage.

S1nce cams of var1ous d1ameters are "required, and since the followers may be cutting t e grove should be adjnstableto meet these diverse conditions. It is also desirable that such a machine should be sturdy,

simple, easily adjusted and manipulat ed,

and capable of performing its machimng bperationssmoothly and accurately. These are objectives of this invention; the at-tain- 'mentof which will become more appareht by reference to theannezed drawings 'which are largely dia rammatic in character.-

Figs. 1, 2 an 3 are a front elevation, an end levation and plan, respectively, and Fi 4: is a layout of the transmission.

f the-intended follower should be replaced by an end-mill and moved in the manrier intended for the follower, a groove v'vouldbe formed which would be accurately conjugate to the follower in all of the latters positioris andthere wold be no cramp- 1ng. But, it would be diflicult to make a cam-cutting machine in that wayand, at the same time, to make the machine readily adustable to accommodate the variations in radii and angular swings required for the different followers that are" needed in the arts.

I have, however, perceived that the above mentioned iiechanical conflict (between the attainment in a single machine of an adequa te range of adjustability and a capacity for developing a geometrically correct camgroove) may be overcome in an essentially practical way by resorting to a converse pr1nciple. That is to say, instead of at tempting t0 cause the millingcutter to duphcate the movement intended for the follower, it may be mounted rigidly and the cam-blank itself will be bodily swung throughout the toolin'g operation; the nat ure of that swing being such as to preserve the relative movement intended between the cam and follower.- In so doing, the cain will simultaneously be rotated about its axis so that its composite motion (during the cutt1ng of the groove) will be a resultant of both the normal motion assigned to the follower and its own normal rotion, but when the cam is completed and subsequently as-.

sembled with its follower, each element will pursue the absolute motion assigned to it.

The end-mill or other appropriate cutter i s indicated diagrammatically by A; it bejournaled ai1y desirablc head B slidabl-y mounted in ways 0 of a frame element C. The screw b serves to shift the head B towards and away from the cam blank and the cutter is power driven, for exrnple, by a suitable gear a deriving motion from a gear such as a splined to a transmissron shaft 1 which in turn is driven in any appropriate rrianner such as will be described. In other words, the cutter is capable of being ed into therotatihg blank until the cam groove or face has been cut to the remg appropriately mounted. on a spindle and 6, Which are coupled to the drive-elem ent f by couplings f and f" so as 2111 to rotate as a unit. Suitable spacing collars may of course be used. For convenience in occasionally mounting a difl'erent master-aam on its arbor, and for succesively putting new cam-blanks on their arbor, thearbor e and al are supported at their ends in journal hoxes G and z and I and h. These journal boxes preferably have readily displaceable caps, as shown, to .facilitate the mpunting and dismounting.

The drive-shaftf is permancntly journaled in a gear bqx H and is driven by a worm wheel F through a suitable train of gears 2, 3, 4 and 5 and a worm 6; this train deriving motion in any appropriate marmer as through a universal shai't 7. These elements constitute the means for impartng rotation to the master-aam and simultaneously tn the camblank during the operation of cutting the groeve.

The arcuate moverhent of the cam blank (counterparting the arcuate niovement of its cooperatin followr) is derived by mounting the, above escribed arbors and their journals on a table arranged to be given what is knovvn as a curvilinear translation. 'lhis is here instanced as a swingable linlnsuspended table; the fixed pivots of the links being carried by adjustable supports and the lengths of the links being equal to the radius abo ut Whch the fellower (te be used subsequcntly with the cam) is intended to oscillate. This link-suspended carriage is indicated by K and, at each end, provides an ear k receiving the floating pivot of whatever link J has heen selected. The fixed pivts of these links are shown carried by shoes L vvhich interfit with vertical slides Zin the uprights M resting on the bed N of the machine. Hand wheels m and their screws serve to effect the raising and lowering of the shoes L during the preliminary settingup of the machine for cutting a given carn; the purpose of this adjustment be1ng t0 enable the axis of the milling cutter to be brought into the same relation with the axis of the cam that the follower will have when subsequently in use. It may here beexplained that it is customary, in designing a cylindrical cam with its arcuate follower, to

space the axis of the cam a distance from the fixed pivot of the follower such that the follower will swing cross the norrnal plane of its fixed ivot and will swing'about as far on one.s e as the other. It may also be here noted that the distance between the fixed pivot of the follower and the axis of the cam is usually such that the ends of the are of the follower willbe as far to one side as the crown of the arc is to the other of the axial plane. Occasionally, however, the design is such that the follower swings mainly at one side of its normal plane and it may here be pointd out that this machine is equally adaptable forcutting either of such types of cylindrical cams.

With the object of insuring a smooth cutting during the machining operation, the table together with its arbors, etc., should be fairly massivc so as te ax oid undue deflection or spring and so as to tend to keep theparts Well down on their bearings and aid the milling cutter in accomplishing its werk; the

blank being turned in such a direction that it rest upon wedge blocks 10 and 11 whch, in

turn, are slidably supported on inclined slideways 12 and 13. Hand levers 0 and 0 may have a rack and pinion en agement vvith these wedge blocks to enable t cm te be read ily shfted into and out of position; the extremity of each lever preferably havin a conventional thrust or index pin adapte to enter any one of a series of holes P and P provided by the bed N ofthe machine so as to hold the levers against movement while the wedge blocks are supporting the table and toenable both levers to be set alike to compel each end of the table to have the same elevation.

Let it be desired to set up the machine for cutting a can1 for a follower havinga radius of say 6". The appropriate master-cam will be inserted and likewise the cam-blank. The hand wheels m will then be turned t0 raise 01 lower the table until the axis of the cutter is in the same relation tothe axis of the blank that the follower will subsequently have with relaticn to the axis of the cam. VVhen this elevation has been attained, the levers O and will be moved until the wedge blocks 10 and 11 are snugly in place. The hand wheels may then le t down the carriage a few thansandths. The pins for the links can then be freely removed and the new links are then substituted; the shoes L being of course moved u and down suflciently to-accommodate the i ength of the new links. -After these links have been s1ibstituted, the lifting strain is taken up by turm'ng the hand wheels m sufiiciently to eigable the wedge blocks to be disengaged. To oscillate the carriage durin the ma chining o leration, there is provi ed a stationary ro er or stud R sulpported in a head 14 which is adjustably c anped (by bolts 15) to a. frame element C previousl mentioried. This frame element is, re erably, longitudinally slidable on the lied along element G.

ways 16, said movement bein accomplished by means of a hand wheel 1% and a worm and worm wheel or turning a pinon 18 which engages a rack 19. '1his enables the stationary roller R (and simultaneously the milling cutter A) to be side-shifted untilthe roller R is aligned with and ready for inscrtion into the groeve of the master-cam. Sometimes the cams have seireral rooves and this sliding construction enab es the fixed roller to be brought into the next groove for positioning' the milling cutter for its next groove, etc.

Occasionally a cam is to be cut where the follower swings chiefiy on one side of its centre and, in that case, it ma be necessary t0 swing the table considerab y to one side before the stationary roller R can be inserted in the groove of the master cam. In that event, the end of a lever bar is nserte d in a notch 20 in the bed N and brought to beer against projectingpin 21 provided by the table or carriage and thereby the carriage is swung to one side temporarily and the stationary roller B een be engaged with its groove.

T0 oppose the thrust of the milling cutter during the machining of the groove, the front of the table is provided with a flatfront hearing surface 22 which, at each end of the table, bears against a wide-face roller S journaled about an upright axis in a standard 23 rigid with the bed of amachine. This front hearing surface 22 is relatively high and the tablehas en opposing bear1ng surface 25on its rear side which is relatively 10W; there being counterpart wide-ace rollers T mounted in rear standards t. These rollers and hearing surface constitute a torq ue-resisting system which enables the table reely to swing under the action of the statidnary roller B. but without any ability to over-turn or be side-shiftedby reason of the pressure of the milling cutter.

Any appropriate power transmission system may of course be incorporated in the machine. For example, a transmission system such as depicted loy Fig. 4 een be em ployed; this consists of a man geer 25, deriving mdtion through a link-belt 26 from a motor 27, and actuating a shaft 28 which enters the geer box29 mounted on the frame At i ts protr'uding end, this shaft 28 carries a change gear 30 meshing with a pinion 31 on a shaft 32 which drives a pinion 33 meshing with gear 34 on the previouslydescribed splined shaft 1. ihereloy thecutter is driven.

To rotate the master-cem and the camelank, the previously described universal shaft 7 is driven by a train as follows: Main shaft 28, Pinions 35 and 86, bevelgears 37 and 38, clutch 39, shaft 40, changegears 41 and 42, shaft 43, change-gears 44 bevel-gears 47 and 48 and in inches per minute. that allthe change-gears 30 and 31 for the speed of the cutter) are finally the shaft 49 connected to the universal shaft.

The advantage of roviding two parsof change-gears, instea of depending on a single pair is that unduly large gears are avoided and the 'attendant is spared mental effort in selecting the gears; it being necessary merely to select gears 44 and for a ratio proportional to the diameter of the cam, and to select for gears 41 and. 42 a ratio corresponding to the feed of the cutter It may be observed arranged on thethree immediately accessible sides of the transmission box W. and, alongside of each pair,may be set a.ratio plate giving the szes of gears for each ratio.

This machine has been shown more or less in diagraminatic form to render more manifest its cardin-al characteristics, and it will be understood-that they may be embodied and arranged in various w ays supplemented by such refinements as may be d1ctated by good machine tool pr-actise.

Having thus claim as new and desire to secure the fellowing combinations and elements, or equiva le1ts thereof, by Letters Patent of the UnitedStates:

1. A cam-makng method which consists in rotating a blank abqut its axis while in contact with a cuttin toolheld a ainst lateral displacement an during sai rotation, imparting to said blank motions-conforming to an arcuate translation to efiect displacements of the axs of said blank with re- (including the pair revealed this invention, I

speel: to said cutting tool in exact accordance with the character of the movement intended for the follower 2. A method of cutt1ng acylindrical cam for a pivotal follower which consists in ro tatin a cam blank in contact with a cutter to said axs in an arcuate path having the same radius as that of the follower.

3. A method for cuttin a ylindrical cam for a pivotal follower wh1ch consists in uniformly rotating a aam-blank and, during said rotation, accomplishing a curvilinear translation of said cam blank in a plane transverse to the axis of the cutter and about centers the radial distance of vvhich are equal to the radius of the ollower.

4. A machine cutting a cylindrical cam comprising a table mounted for curvilnear translation; a master-cam and a cam-blank mounted to rotate synchronously about parallel axes; a stationary element cooperating with the groove of the master cam; and a non-Shiftable cutter engaging the cam blank.

5. A machine for cutting a cylindrical cam.combining a rock table;

cam combining a rock-table; gui de means or holding said table in its longitudinal plane; links fox determining the radius of the curvlinear translation of said table in its longitudinal plane; a master-cam and a cam-blank mountd on said table; a fixecl stud engaging the groeve.of said mastercam; a non-shiftuble cutter engaging the cam-blank, the axes of said stud and cutter beingtransverse to the plane of osillation of said t-able; and means for syi1chronously rotating said cam and cam blank whereby said fixecl stud may accomplish a curvilinear translation of said table 6. A method of cutting a cylinclri'cal cam for a pivotal follower which consists in mtating a cam blank downwardly against a fixed cutter, and simultaneously causing the cam blank to translate in an arcuate path having the same radius as that of the follower.

7. A cam cutting. machine coinbining a fixed cutter; a rotatable arbor arnanged transverselyto the axis of said cutter; a support for said arbor; parallel links for carrying said support; and fixed pilvots fo1 said links, said fixed pivotsbeing adjustable transversely t0 said axis.

8. A machine cutting a cylindrica'l cam comprising a table mounted '01 curvilinear translation; a master-cam and a cam-blank mounted to rotate coaxially; a stationary element cooperating with the groeve of the master cam t0 efl'ect longitudinal displacements thereof; a non-shiftable cutter engaging the cam blank; and means fox rotacing said aam-blank clownwardly 'against sa1d cutter.

9. A machine for cutting a cylindrical guide means f01 holding said table in its longitudinal plane; detachable links for determining the radius of the curvilinear translation of said table in its longitdinal plane; a mastercam and. a aam-blank mounted en said table; a. fixed stud engaging. the groove of said master-cam; a non-shiftable cutter engaging the cam-blank, the axes q sad stn'd and cutter being transveise to the plane of scillation of said table; temporary supports for carrying theweight of saicl fable during a replacement of itslinks; and means for synehronously rotating said cam and cam blank whereby said fixed Stud may accomplish a curvil1near translation of said table.

10. Acam cutting machine combining a fixed cutter; a rotatable arb01 arranged transversely to the axis of said cutter; a table for said arbor; parallel links for supporting said table; and abutment members fox resisting any tendency for the table tp turn about its longitudinal axis.

11.A machine cutting a ylindrical cam comprising a. table mounted lf0i curvilinear transltion; a master-cam and a cam-blank mountecl thereon to rotate synchronously; a stationary stuol cooperating with the groove of the master cam; a non-shiftable cutter cooperating With the cam-lolank; and a laterally adjustable frame upon which said stud and cutter are mounted.

12. A machine for cutting a cylndrical cam combining a rock table; guide means )l' restraining said table te movement in a longitudinal plane; links for determining the rock-are of said table in its longitudinal plane; a master-cam and a cam-blank mountcd on said table; means f01' synchronously rotating said cam and cam blank whereby a fixe d stud may accomplish a cu1wilinear translation of saicl table; a nor mally fixed stud engaging the groeve of said master-aam; a non-shiftable cutter engaging the cam-blank, the axes of said stud and cutter bein transverse to the plane of oscillation of sa1d table; and a frame carrying said stud and cutter and adjustzible laterally as a unit therewith, said stnd and cutter being independently adjustable on said frame towards said cam and cam-blank.

13A gear-clriven mechanism comprisng two independently variable sets of changegears; the one set of change-gears being aclapted espeeially to meet one variety of conditions, and the other set to meetanother variety of conditions; and a transmission 'comprehending said two sets in serial relation. whereby conjointly they will transmit moti0n at a single resultant ratio conforming to both of said conditions.

In witness whereof, I have hereunto subscribed my name.

ADOLPH L. DE LEEUW. 

